1. Field of the Invention
The present invention relates to structure for fixing a flat cable to a cylindrical rotator and, more particularly, to structure for fixing the flat cable of the brushless electric signal transmitter of a vehicle steering system to the cylindrical rotator of the transmitter. The rotator is fixed to the steering wheel. The transmitter transmits signals between parts on the steering wheel and the steering column.
2. Description of the Prior Art
In recent years, as automobiles have been electronically controlled, the steering wheels have been fitted with switches for electronic control and electrical equipments for air bags etc. There is a need to electrically wire the switches and equipments to parts on the steering columns. Each steering wheel can rotate by a finite number of turns in both directions. In order to electrically interconnect a part on the steering wheel shaft and a part on the steering column, there is a need of a brush between the parts or a flexible cable between them, which can follow the wheel rotation.
Because the brush is a mechanically sliding contact, which is less reliable, there has been proposed a brushless electric signal transmitter with a flexible flat cable having a number of lead wires. The transmitter includes a rotator fixed to the steering wheel shaft of an automobile, and a housing fixed to the steering column and surrounding the rotator. The cable is either wound vortically, or extends vortically and is turned backward midway, between the rotator and housing. As the shaft rotates, the cable moves in the housing.
There is a need to connect the cable with the lead wires to switches on the steering wheel, and to circuits on the steering column. For this purpose, one or both end portions of the cable are folded at a right angle to extend outward in parallel to the wheel shaft.
For example, Japanese Patent Second (after exam.) Publication H.2-41,150 and First (before exam.) Publication H.4-218,286 each disclose a brushless electric signal transmitter with both end portions of a flat cable folded at a right angle and extending out of the transmitter.
Generally in a conventional brushless electric signal transmitter, as disclosed in the above publications, a plastic or resinous cover keeps the flat cable folded at a right angle. The cover is fitted in a recess formed in the transmitter; the cable extends out of the cover in parallel to the transmitter axis of rotation.
In order to form such a cover at each end of the cable, there is a need to place the cable as folded at a right angle in an injection mold for insert molding. This process involves a number of steps and costly apparatus.